Canine Cancer: Raw vs Kibble Part 2

Dry Kibbled Food and Cancer

“Meat meal” powder is an ingredient in most dry cat food and dog food. It is made from abattoir and fish-processing factory remnants, inedible for humans. They are processed under high temperature and dehydrating the resulting pungent gloop into a dry powder for storage and transport. Meat meals eventually go into kibble as a cheap source of protein, allowing the manufacturer to claim meat content.

Compared to real meat, this product is much higher in ‘ash’, poorly digested minerals. Protein digestibility is 61% vs 95% in fresh meat. Lysine is an amino acid greatly affected by this production process. Essential in the body for immune function, calcium absorption and the formation of connective tissue collagen, in meat meal, available Lysine is 41g per kg protein, in real meat, about 65g/kg protein. Meat meal contains less available vitamins A, D and E, meaning synthetic vitamins must be added to kibble.

The major unregulated and unnecessary (yes, even nutrition textbooks agree) ingredient, is carbohydrate. It’s usually grain, but often maize, sweet potato or oats, depending on what’s fashionable and cheap. To these edifying building blocks is often added: Corn Gluten Meal, fruit & veg (sometimes and mostly powdered from China), preservatives, stabilisers, gelling agents, synthetic vitamins and minerals and palatability enhancers like yeast, fat, sweeteners or concentrated flavours. Now you know why we’re discussing kibble and cancer.

Because of the ingredients in kibble, the processing, storage and the repetitive feeding (one food for the whole life of the poor dog is typical), they can have a massive negative effect on canine health. If you examine a bowl of any given dried dog food, you won’t usually find high levels of toxins. If you study one cigarette, you won’t find much tar and nicotine. It’s the lifelong repetition of inferior quality ingredients and carcinogens that does the damage.

Ultra-processed food is a thing, a phenomenon. It even has a definition. Michael J. Gibney, in his 2019 paper on the subject, offers this most up to date definition: ‘Industrial formulations typically with five or more and usually many ingredients. Besides salt, sugar, oils, and fats, ingredients of ultra-processed foods include food substances not commonly used in culinary preparations, such as hydrolysed protein, modified starches, and hydrogenated or interesterified oils, and additives whose purpose is to imitate sensorial qualities of unprocessed or minimally processed foods and their culinary preparations or to disguise undesirable qualities of the final product, such as colourants, flavourings, non-sugar sweeteners, emulsifiers, humectants, sequestrants, and firming, bulking, de-foaming, anticaking, and glazing agents.’ I think you’ll agree that kibble most definitely comes under this definition.

And unfortunately, the 2015 paper by Luiten et al. says it all regarding the value and availability of the stuff. In their study, based in New Zealand, they state: ‘Ultra-processed foods have the worst nutrient profile, yet they are the most available packaged products in a sample of New Zealand supermarkets.’ The same is true, unfortunately in every country on earth.

Why Dry Kibble is So Bad

What are the mechanics of the harmful effects of kibble? Stick with us, and we’ll go through a list: 

  1. Feeding a carnivore (or a very carnivorous omnivore, if you like) continuously on a high carb diet is madness. It distorts the gut microbiome, which responds to the inappropriate levels of carb and sugars in artificial food, corrupting the burning epicentre of every aspect of health. John Cryan in his book ‘Psychobiome’ went so far as to say, about the Gut-Brain connection that ‘If microbes are controlling the brain [from the gut], then microbes are controlling everything.’ Kibble changes the microbiome significantly, as documented in Milena Schmidt’s 2018 paper entitled ‘The faecal microbiome and metabolome differ between dogs fed Bones and Raw Food (BARF) diets and dogs fed commercial diets.’ Kiley Algya and her team studied this further, the same year, in their paper, ‘Apparent total-tract macronutrient digestibility, serum chemistry, urinalysis, and faecal characteristics, metabolites and microbiota of adult dogs fed extruded, mildly cooked, and raw diets.’ They concluded, ‘Compared to the extruded diet, these diets had greater nutrient digestibility, resulted in reduced blood triglyceride concentrations, and shifted faecal microbiota populations and metabolite concentrations.’ A disturbed gut microbiome is associated with Irritable Bowel Syndrome (IBD) in humans and dogs. IBD is, in turn, a significant risk factor for colorectal cancer in humans. Few studies are available yet to establish the same link in dogs, but it’s likely to be similar.
  2. High Glycaemic index carbohydrates promote hyperinsulinemia (excess insulin production), which is associated with Type 2 diabetes, gout, Alzheimer’s disease, atherosclerosis and cancer in humans. In multiple studies, diabetes has been linked with increased risk of several types of cancers, including a three-times higher risk of colon-rectal cancer. (Anand et al., 2008; Divisi, 2006; Donaldson, 2004; Nahleh, Bhatti & Mal, 2011) From Nutrigenomics, byDr. Jean Dodds. 
  3. Epigenetics, the molecules controlling how the body reads DNA, are very much influenced, for better and for worse by (raw and kibbled, respectively) food. For example, BHA, BHT and Ethoxyquin are carcinogenic preservatives long banned in the human food chain but are permitted in the UK pet food industry as EC permitted antioxidants E320, E321 and E324. They can all used in kibbled dog food dogs gets every day for an entire life stage or even for life.
  4. Overweight and obese dogs account for up to 70% of dogs in the UK and the USA. Obesity is very much influenced by the food you eat. We’re feeding dogs on high carb diets, a sure-fire recipe in humans for obesity. In humans, Jean Dodds’ Nutrigenomics, tells us: Breast, Cervical, Colon, Endometrial, Esophageal, Gastric, Gall bladder, Liver, Multiple myeloma, Non-Hodgkin’s lymphoma, Ovarian, Pancreatic, Rectal, Renal and Uterine cancers. Dogs don’t stand a chance! Incredibly, the response of veterinary nutritionists who advocate kibble feeding to control obesity is to “just control the amount that you feed”. Surely if it were this easy, we would not have gone from about 20% obesity in the ’80s, and 90’s to what we have today? They conveniently forget they advocate high carb daily for life and wonder why they have a 75% failure rate in slimming fat dogs.
  5. Counterintuitively, the work of Dr Mark Roberts on raw and kibble fed dogs shows that dogs on high carb diets have more elevated blood triglyceride (fat) levels than raw fed dogs on higher-fat diets! He argues this is why we see an increase in pancreatitis in the modern dog. Another study by Watson et al. in 2007 examined the pancreases of 200 dogs who had died from non-pancreatic disease. They found that 34% of the dogs showing no sign of pancreatitis at death had tissue changes indicative of long-term pancreatic disease. Cavaliers, Collies and Boxers were the main breeds affected in the study. If most of these dogs were likely to have been fed kibble, there seems a possibility that if you feed your dog kibble, you have a one in three chance of giving them pancreatic disease. Obesity is another factor contributing to pancreatitis. Long-term inflammation is a risk factor for cancer in any tissue.
  6. When you heat proteins, fats and sugars together, as you do when making kibble, carcinogens called Advanced Glycation End-products (AGEs) are made. These toxins are a bio-marker implicated in humans in ageing and the development or worsening, of many degenerative diseases, such as diabetes, atherosclerosis, chronic kidney disease, Alzheimer’s disease and cancers.
  7. An independent laboratory test of dry dog foods commissioned by the Environmental Working Group (EWG) found that eight out of 10 major US brands sold for puppies and adults contained fluoride. Levels were discovered between 1.6 and 2.5 times higher than the US Environmental Protection Agency’s maximum legal dose in drinking water. The foods all included a bone meal, meat meal or meat by-product meal. Fluoride in bones is considered a risk factor for Osteosarcoma, a terrible bone cancer that mainly affects the long bones of large breed dogs. Boxer Dogs, Doberman Pinschers, Golden Retrievers, German Shepherd Dogs, Great Danes, Great Pyrenees, Greyhounds, Irish Setters, Irish Wolfhounds, Labrador Retrievers, Rottweilers, Saint Bernards, and Weimaraners are the breeds most affected by this cruel disease.
  8. Periodontal disease is prevalent in the kibble eating population. Experience, common sense and studies confirm this. Marx et al. in 2016 looked at beagles chewing bones. They concluded, ‘Chewing raw bovine bones was an effective method of removing dental calculus in dogs.’ In 2012, Rene Carlson, then President of the AVMA stated, ‘It’s estimated that by the age of two, 80 per cent of dogs and 70 per cent of cats have some form of periodontal disease.’ Dr. Tom Lonsdale, in his landmark 2001 book ‘Raw Meaty Bones Promote Health’, describes how periodontal disease causes inflammation and damage to the gum margin leading to bacterial endotoxins, cytokines and free radicals entering the bloodstream to pollute the whole body. He quotes Stohl on free radicals: ‘Oxidative stress associated with the production of reactive oxygen species is believed to be involved not only in the toxicity of xenobiotics [foreign chemicals] but also in the pathophysiology of ageing, and various age-related diseases, including cataracts, atherosclerosis, neoplastic diseases [cancer], diabetes, diabetic retinopathy, chronic inflammatory diseases of the gastrointestinal tract, ageing of the skin, diseases associated with cartilage, Alzheimer’s disease and other neurological disorders.’

You now have eight reasons to distrust kibbled food. Read Part 3 to learn how beneficial, how protective raw food is against canine cancer.

Back to Part 1.

Nick Thompson

BSc (Hons) Path Sci., BVM&S, VetMFHom, MRCVS. Founding President of the Raw Feeding Veterinary Society. Petplan Vet of the Year Nominee 2009, 2015, 2017, 2018 & 2020. The practice of the Year Nominee 2018.


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